FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene is a member of the protein-tyrosine kinase oncogene family. It encodes a membrane-associated tyrosine kinase that has been implicated in the control of cell growth. The protein associates with the p85 subunit of phosphatidylinositol 3-kinase and interacts with the fyn-binding protein. Alternatively spliced transcript variants encoding distinct isoforms exist. [provided by RefSeq, Jul 2008] PHENOTYPE: Different targeted allele homozygotes show different defects, including seizure susceptibility, anxiety, impaired suckling, myelination, LTP and spatial learning, and defects in immune system, circadian rhythm, testes weight and olfactory bulb formation. [provided by MGI curators]